1. Field of the Invention
The present invention relates to a silver halide color photographic light-sensitive material in which a contact fog caused by yellow colloidal silver in a yellow filter layer is suppressed.
2. Description of the Related Art
Normally, a silver halide color photographic light-sensitive material having blue-, green-, and red-sensitive silver halide emulsion layers on a support has unnecessary light sensitivity in a blue light region in a spectral sensitivity distribution of the green and red-sensitive emulsion layers.
In order to obtain good color reproducibility, however, it is preferred that the green-sensitive emulsion layer has color sensitivity mainly in only a green light region and the red-sensitive emulsion layer has color sensitivity mainly in only a red light region.
Therefore, a hydrophilic colloid layer which is arranged so as to face the support across the green-and/or red-sensitive emulsion layers is dyed in yellow to reduce an amount of blue light amount entering the green- and/or red-sensitive emulsion layers, thereby improving the color reproducibility.
A component which dyes the hydrophilic colloid layer in yellow must be discharged or discolored by development. For this reason, yellow colloidal silver or a yellow dye such as a pyrazoloneoxonol dye described in British Patent No. 506,385 or an oxonol barbiturate dye described in U.S. Pat. No. 3,247,127 is normally used.
The yellow dye, however, diffuses to another layer (e.g., if the dye diffuses to a blue-sensitive emulsion layer, the sensitivity of the blue-sensitive layer is lowered) because its dyeing property is bad, or it has a poor discoloring property. Therefore, yellow colloidal silver is normally used.
This yellow colloidal silver can be prepared by various methods.
Satoshi Inoue, "Inorganic Chemistry Manufacturing Test", P. 647 describes, e.g., a method of reducing silver nitrate with dextrin under alkaline conditions, a method of reducing silver nitrate with tannin under alkaline conditions, a method of reducing silver nitrate with hydrazine, and a method of reducing silver oxide with sodium carbonate and hydrogen peroxide in the presence of a silver sol reduced with phosphorus.
When yellow colloidal silver conventionally used in a silver halide color photographic light-sensitive material is dispersed in a hydrophilic colloid layer such as a gelatin layer, its maximum absorption peak appears at 420 nm to 430 nm, and 1/4 absorption of the maximum absorption at the longer wavelength side occurs within the range of 480 to less than 500 nm.
If the conventional colloidal silver as described above is used, however, a fog in a light-sensitive silver halide emulsion layer adjacent to a layer in which the colloidal silvers are included is undesirably increased.
A degree of the increase in fog caused by the colloidal silver differs in accordance with a grain size of light-sensitive silver halide grains. That is, as the grain size is decreased, the fog is increased. In particular, if a grain size of silver halide grains in a light-sensitive silver halide emulsion layer adjacent to a yellow colloidal silver layer is small, a fog is significantly increased.
On the contrary, graininess of a light-sensitive silver halide emulsion is normally improved as a grain size of the emulsion is decreased. Therefore, in order to improve the graininess, studies for increasing a sensitivity/grain size ratio have been continuously made by those skilled in the art. According to the studies made by the present inventors, however, as the grain size of silver halide grains is decreased, the fog caused by colloidal silver used in a yellow filter layer is increased, as described above. Especially when the grain size is 0.4 .mu.m or less, an increase in fog is large.
The following method is known as a method of suppressing the fog. That is, Published Examined Japanese Patent Application No. 59-47305 discloses a method of adding I.sup.- to a hydrophilic coloid layer containing colloidal silver or an adjacent non-light-sensitive layer, and Zhun, Nauch, i Priklad, Fot, i Kinematografii, 6, 2256 (1961) discloses a method of adding various non-diffusing reducing agents to a colloidal silver-containing filter layer.
When I.sup.- is added as described above, however, development of a light-sensitive silver halide emulsion is suppressed, or I.sup.- is accumulated in a bleaching and fixing solution used in a development step to reduce a bleaching and fixing speed.
In the method of adding the non-diffusing reducing agent to the filter layer, a bleaching speed of colloidal silver in a development step is reduced, or a fog of a light-sensitive silver halide emulsion is increased when a light-sensitive material is stored under high-temperature and high-humidity conditions.